294.1 🎓 醫孞生版

294.1.0.1 📌 䞀頁重點

294.1.0.1.1 Athletic Heart Syndrome
294.1.0.1.1.1 Physiologic Adaptations to Training
  • Endurance (running, cycling, swimming): predominantly volume overload → eccentric LVH + LV dilation + larger SV
  • Strength / power (weightlifting): predominantly pressure overload → concentric LVH
  • Combined (rowing, cycling): mixed
294.1.0.1.1.2 Findings (Adapted Heart)
  • LVH (concentric or eccentric)
  • LV dilation in endurance athletes (LVEDD up to 70 mm)
  • RV dilation in endurance athletes
  • Increased SV, lower resting HR
  • Bradycardia at rest (HR 40-50 common)
  • First-degree AV block (PR > 200 ms)
  • Wenckebach (Mobitz I) in some
  • Early repolarization
  • Voltage criteria for LVH on ECG without clinical significance
294.1.0.1.1.3 Distinguish From Pathology
  • ECG criteria (Seattle, International, Athletes vs HCM)
  • Echo + CMR
  • Family history
  • Symptoms (none in physiologic)
  • Detraining: physiologic changes reverse over weeks
294.1.0.1.2 Sudden Cardiac Death (SCD) in Athletes
294.1.0.1.2.1 Epidemiology
  • Rare but devastating
  • Incidence: 1 per 50,000-200,000 athlete-years
  • Higher in: African American athletes, basketball, football, soccer
  • Male > female (5-10:1)
294.1.0.1.2.2 Causes by Age

Young (< 35 yo): 1. Hypertrophic cardiomyopathy (HCM) — #1 in USA 2. Anomalous coronary artery origin (#1 in Italy autopsy data; LAD from R sinus or RCA from L sinus) 3. ARVC (Arrhythmogenic RV cardiomyopathy) 4. Long QT syndrome (LQTS) 5. CPVT (Catecholaminergic polymorphic VT) 6. Brugada syndrome 7. WPW + AF → VF 8. Myocarditis (viral, COVID-19) 9. Marfan with aortic dissection 10. Commotio cordis (blunt chest impact during vulnerable T wave period) 11. Idiopathic VF 12. Mitral valve prolapse + arrhythmic (rare) 13. CAD (increasingly recognized in some teens with extreme RF)

Older (> 35 yo): 1. Coronary artery disease (#1 by far) 2. Cardiomyopathies 3. Valvular heart disease

294.1.0.1.2.3 Pre-Participation Screening (PPS)

Components: - History: chest pain, dyspnea, syncope, palpitations, family hx of SCD < 50, family hx of inherited heart conditions - Physical examination: BP, murmurs, Marfan features, peripheral pulses - ECG (controversial in US): adds sensitivity

Different Approaches: - Italian model (since 1982): mandatory ECG + history + physical - AHA / US: history + physical; ECG selectively - ESC / IOC: ECG recommended - European trend toward ECG inclusion

294.1.0.1.2.4 Italian Model Outcomes
  • ↓ SCD ~ 90% over 25 years (Corrado et al, 2006)
  • Disqualified many false positives also (controversial)
294.1.0.1.3 ECG Interpretation in Athletes (Seattle / International Criteria)
294.1.0.1.3.1 “Normal” Variants in Athletes
  • Sinus bradycardia
  • Sinus arrhythmia
  • First-degree AV block
  • Wenckebach (Mobitz I)
  • Right bundle branch block (incomplete or complete with normal QRS in some)
  • Voltage criteria for LVH alone
  • Early repolarization
  • T-wave inversion in V1-V3 (in some young black athletes)
294.1.0.1.3.2 Abnormal in Athletes — Investigate
  • T-wave inversion in lateral or inferolateral leads (NOT physiologic)
  • Pathologic Q waves
  • ST depression
  • Complete LBBB
  • Mobitz II or higher-degree AV block
  • VPCs > 2 per 10-second strip
  • Long QT (corrected > 460 men, > 470 women, > 480 children)
  • Brugada pattern
  • WPW
  • Epsilon waves (ARVC)
294.1.0.1.4 Specific Conditions
294.1.0.1.4.1 Hypertrophic Cardiomyopathy (HCM)
  • See Ch270 + 268
  • Sarcomere mutations (MYH7, MYBPC3, TNNT2)
  • LV wall thickness ≥ 15 mm in adults
  • Family screening
  • Risk stratification: family hx of SCD, syncope, NSVT, ↑ wall thickness ≥ 30 mm, abnormal BP exercise, LGE

Athletes with HCM: - 2024 ACC/AHA + LIVE-HCM (2023): moderate-intensity exercise safe (vs older blanket prohibition) - ICD does NOT automatically disqualify - Multidisciplinary assessment - Individual + competitive decisions

294.1.0.1.4.2 Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC)
  • Desmosomal mutations (PKP2, DSP, DSG2)
  • RV fibrofatty replacement
  • Triangle of dysplasia
  • VT with LBBB morphology
  • Epsilon waves on ECG
  • Often presents in athletes with VT during exercise
  • ICD + restrict competitive sports
294.1.0.1.4.3 Long QT Syndrome (LQTS)
  • LQT1: KCNQ1 — exercise-induced (swimming)
  • LQT2: KCNH2 — startle, postpartum
  • LQT3: SCN5A — sleep
  • Treatment: β-blocker (nadolol, propranolol), ICD if recurrent, lifestyle (avoid QT-prolonging meds)
  • LQT1 + swimming avoidance
294.1.0.1.4.4 Anomalous Coronary Artery
  • L coronary from R sinus / R coronary from L sinus (course between PA + aorta = interarterial = risk)
  • Mostly asymptomatic until severe
  • Diagnosis: CTA, cath, MRA
  • Treatment: surgical re-implantation or unroofing
  • Activity restrictions vary
294.1.0.1.4.5 Commotio Cordis
  • Sudden blunt impact to chest during vulnerable T wave period (10-20 ms)
  • Often baseball, lacrosse, hockey
  • Triggers VF
  • AED is treatment + saves lives (Damar Hamlin 2023 NFL incident high-profile)
294.1.0.1.5 COVID-19 + Athletes
294.1.0.1.5.1 Risk
  • Acute myocarditis
  • Post-acute sequelae (PASC, long COVID)
  • Risk of arrhythmia, SCD during recovery
294.1.0.1.5.2 Return to Play
  • Mild COVID + asymptomatic: 3-7 days rest
  • Moderate symptoms: 10-day rest + symptom resolution
  • Cardiac symptoms / hospitalization: cardiology evaluation
  • Suspected myocarditis: 3-6 month exercise restriction; CMR + serial follow-up
  • Lake Louise CMR criteria + clinical assessment
294.1.0.1.6 Cardiac Rehabilitation + Athletes
294.1.0.1.6.1 Post-Cardiac Event
  • Exercise prescription tailored
  • Slower progression in recovery
  • Monitor cardiac biomarkers
  • Multidisciplinary
294.1.0.1.6.2 Return to Competition
  • Based on objective testing (CPET, echo, holter, ICD interrogation if applicable)
  • Sport-specific demands considered
294.1.0.1.7 AED + Public Education
294.1.0.1.7.1 Survival Improvement
  • Damar Hamlin 2023 NFL: bystander CPR + early AED → survived
  • Christian Eriksen 2021 Euros: similar
  • AED placement at sport venues critical

294.1.0.2 🩺 床邊速查

  • Athletic heart: eccentric LVH (endurance) or concentric (strength); bradycardia, 1° AV block, voltage criteria LVH — all physiologic
  • SCD young athletes: HCM (US), anomalous coronary (Italy), ARVC, LQT/Brugada, myocarditis
  • SCD older athletes: CAD (#1)
  • HCM athletes 2024: moderate exercise OK (LIVE-HCM); ICD ≠ automatic disqualification
  • Commotio cordis: blunt chest impact during T wave → VF → AED + CPR
  • COVID-19 myocarditis: 3-6 mo exercise restriction; CMR + monitoring
  • Pre-participation: history + physical; Italian model adds ECG (↓ SCD ~ 90%)